The subject matter of this application was filed under the Disclosure Document Program of the Patent Office on Aug. 19, 1992, and received Disclosure Document Number 315,761.
Canoes and kayak-type boats provide the most efficient means for one or two people to propel themselves through the water without the use of a motor. The narrow hull not only reduces water resistance, but enables the operator to conveniently access the water on both sides of the boat. This is more important in a kayak, in which the beam of the boat must be narrow enough that the paddler can paddle on both sides of the boat without moving from his seated position.
Kayaks and canoes are much more agile than rowboats. Paddling provides an obvious maneuverability and agility advantage over rowing as a means of propelling a small boat, even if they are the same hull shape.
The big disadvantage of paddling over rowing is the inevitable yaw effect produced every time the paddle is stroked. Since the paddle only strokes one side of the boat at a time, it tends to yaw in the opposite direction.
Two-passenger canoes reduce this effect somewhat by the use of simultaneous paddling on opposite sides of the boat by the two canoers. Nonetheless, since the paddlers are spaced apart, the yaw effect still exists, and coordination of the two canoers is difficult unless they are experienced working as a team.
The extent of the problem with kayaks depends on the type of kayak. Typically, a kayak is a single-passenger vessel, so that the dual paddling possible in canoes cannot be done. However there are some sea kayaks which are dual passenger. Paddlers in a sea kayak, unlike canoe paddlers, must paddle in a synchronized fashion because they are seated so close together. Thus, the problem is not simplified, although sea kayaks have a keel and usually a rudder which helps them maintain course.
More traditional kayaks and river-running kayaks have no keel at all, and have almost no directional preference. It is very difficult even for an experienced paddler to paddle a very short, state-of-the-art river runner in a straight line. These boats are designed specifically to make quick turns when going downstream to avoid rocks. When paddling these boats on a lake or other open stretch of water, many of them will refuse to go straight, and cause the paddler to spend 20 or 30% of his paddling energy keeping the boat straight rather than moving it forward.
There is a need, therefore, for a new type of kayak-type boat paddle and a technique for using it which preservers the maneuverability characteristics of paddle craft but eliminates or reduces the drawback of propelling the boat from one side or the other during any one paddle stroke.